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#26 pre amp

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Are you referring to the 20-25 ohm filament resistor? If so, i am going with 100w rated resistor. I tend to overkill when it comes to heat.
If you use only 01a tube, the filament bias resistor dissipation is moderated.
 

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I always use choke input for my filament bias supplies and this requires a different calculation based on the resistance of the chokes. I get them from Hammond. Easier to use the 01A in terms of filament supply, and better sound. As long as you are not driving the outputs which needs more current. For more current I use the 2P29L at 15mA. I like the sound, and this actually does drive my PSE 4P1L outputs. The 10Y is better but not by too much, and since my system is on 24/7 I don't want to wear my stock out.
 
400mA gives you nice headroom for a 01A. You could use a couple for each filament. That would give you a really nice clean supply - vital in filament bias. You'd need to use a mains transformer with a higher voltage since you'd be losing volts. One thing about using Ale's gyrator with 01As, which is a good combination, is that the gyrator needs good condition 01As to work properly - not weak ones. And for good condition 01As the later ST shape ones are a better bet. Should really be tested as high emission.
 
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Andy thanks for the reply,

You'd need to use a mains transformer with a higher voltage since you'd be losing volts.

My main transformer output is 18v at 2A. So that should be plenty to work with.
And for good condition 01As the later ST shape ones are a better bet

I was under the assumption that the globes sounded better than the ST. I just bought 3 (supposedly) NOS Globes but I have no way of testing them. My tube tester is not capable of checking ancient tubes. But I will look for ST tubes.

Do you think my little 0.5hy DCR 18ohm chokes can be utilized for choke input for 01a? I can play around since i have a bunch of them.

thanks,
 
Hi Guys, Slightly OT question. Am gathering psu parts to build up Ale's 01a gen 2 preamp. Regarding the LCLC supply, is there any advantage to be had if I Tee off after the first capacitor & supply each channel with it's own choke & capacitor ? Meaning in all there'll be 3 chokes instead.

Thks
 
10v p-p tube signal on a 100k pot will outperform virtually any volume device.
3db per step is almost useless.
Depends on what you mean by outperform. A TVC on the output of my 01A cuts out the hum, which with the excessive gain of the gyrator, can be unbearable. My power amp is 250W at 1V input! The 26 suits that better, with a pot on the input.
 
I was under the assumption that the globes sounded better than the ST.

I can't hear much difference - these 01A tubes are so old that the condition of the tube is probably more important than the type of tube. STs are newer generally. I have a bunch of globes that don't work with Ale's gyrator - the voltages won't come into range with the stated component values. I ended up with only a small part of my stock being usable, and those were almost all ST shape. Maybe I had some component failures in the gyrators - couldn't find the reason since I'm not good with solid state. Anyway, for globes I've been using plate chokes as an alternative. I like plate chokes anyway so I've also been using them with the 2P29L, my daily listen, which as far as I know also works just fine with Ale's gyrator. So what I'd say is start with Ale's gyrator and see how it goes with your globes. If you have any issues you can always swap in a 2P29L, which I prefer to the 26 plus it's a simpler filament supply.